# Preoperative iron supplementation in non-anemic patients undergoing major surgery: a systematic review and meta-analysis

## TL;DR

Giving iron before surgery to non-anemic patients may reduce the need for blood transfusions, especially in cardiac procedures.

## Contribution

This study is the first to systematically evaluate preoperative iron supplementation's effect on transfusion risk in non-anemic patients.

## Key findings

- Preoperative iron reduced transfusion risk by 46% in non-anemic patients.
- Iron supplementation increased hemoglobin levels on the first postoperative day.
- No significant hemoglobin difference was found during the first postoperative week.

## Abstract

Blood transfusions are associated with increased morbidity and mortality, and maintaining global blood supplies can be a challenge. This systematic review investigates the impact of preoperative iron supplementation on the risk of blood transfusion among non-anemic patients undergoing major surgeries.

We conducted a systematic search of PubMed, Embase, and Cochrane Central for randomized controlled trials published up to May 2024. Studies involving the use of erythropoietin, or patients already using iron supplementation when trial randomization was conducted were excluded. Outcomes assessed included the number of individuals who received blood transfusions, and mean hemoglobin levels at the first day and by the first postoperative week.

A total of 1,162 non-anemic patients from 9 studies were included. Of these, 54% received preoperative iron supplementation. The average age was 71 years, and 44% were women. Preoperative iron supplementation was associated with a significantly lower risk of receiving a blood transfusion (OR = 0.54; 95% CI 0.40 to 0.75; p < 0.001). At the first postoperative day, the iron supplementation group had significantly higher mean hemoglobin levels compared to the no-treatment group (MD = 0.22 g.dL-1; 95% CI 0.02 to 0.42; p = 0.03). However, the pooled results could not rule out the null hypothesis for the difference in mean hemoglobin levels throughout the first week (MD = 0.12 g.dL-1; 95% CI -0.12 to 0.35; p = 0.34).

Preoperative intravenous iron supplementation in non-anemic patients undergoing major surgeries, particularly cardiac procedures, significantly reduces transfusion requirements. However, the benefits of oral iron remain uncertain, and further research is warranted to establish standardized perioperative supplementation protocols.

CRD42024552559.